DSPINT=0
DSPINT=1
CPU writes 1
to DSPINT bit
Interrupt
pending
Host writes 0
to DSPINT bit
No interrupt/
interrupt
cleared
Host writes 0 or 1
to DSPINT bit
CPU writes 0
to DSPINT bit
CPU writes 0 or 1
to DSPINT bit
Host writes 1
to DSPINT bit
(interrupt generated
to CPU)
(A)
Architecture
976
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Host Port Interface (HPI)
21.2.9 Interrupt Support
The host can interrupt the CPU via the DSPINT bit in HPIC, as described in
. The CPU
can send an interrupt to the host by using the HINT bit in HPIC, as described in
21.2.9.1 DSPINT Bit: Host-to-CPU Interrupts
The DSPINT bit in HPIC allows the host to send an interrupt request to the CPU. The use of the DSPINT
bit is summarized in
.
Figure 21-15. Host-to-CPU Interrupt State Diagram
A
When the DSPINT bit transitions from 0 to 1, an interrupt is generated to the CPU. No new interrupt can be generated
until the CPU has cleared the bit (DSPINT = 0).
To interrupt the CPU, the host must:
1. Drive both UHPI_HCNTL1 and UHPI_HCNTL0 low to request a write to HPIC.
2. Write 1 to the DSPINT bit in HPIC.
When the host sets the DSPINT bit, the HPI generates an interrupt pulse to the CPU. If this maskable
interrupt is properly enabled in the CPU, the CPU executes the corresponding interrupt service routine
(ISR).
Before the host can use DSPINT to generate a subsequent interrupt to the CPU, the CPU must
acknowledge the current interrupt by writing a 1 to the DSPINT bit. When the CPU writes 1, DSPINT is
forced to 0. The host should verify that DSPINT = 0 before generating subsequent interrupts. While
DSPINT = 1, host writes to the DSPINT bit do not generate an interrupt pulse.
Writes of 0 have no effect. A hardware reset immediately clears DSPINT and thus clears an active host-to-
CPU interrupt.